My girlfriend and I stayed at Mongkol's place for a night in Bangkok. The location was perfect for the short time we were there. It was about 40 minutes from BKK and once we arrived everything was within walking distance - the grand palace is 2 blocks away.
Our flight was delayed and we showed up much later than expected but Mongkol was very accommodating. He told the taxi driver exactly how to get there for us which really helped because of the language barrier. When I showed the taxi the address, the guy didn't have a clue nor did he use gps so it was great for Mongkol to be so available. FYI the price of the cab should only cost from 300-400 Baht (grab a metered taxi at the airport and make sure they start the meter. A guy who was staying at our same palace was saying it cost him 700 because his driver hadn't.) We would've loved to stay longer and next time we're in Bangkok, we'll definitely be staying at Mongkol's place.
The room itself was perfect and everything was as described on airbnb. It was hot outside but the a/c in the room kept cold. I'd highly recommend it to anyone. He was a gracious and kind host.